During the past year we have developed a new technique for removing individual, identified nerve cells from the brain of the leech. We can now maintain in culture for periods of six weeks or more single sensory cells, montoneurons and interneurons. Such cells survive well and maintain their electrical properties. In addition we have shown that within about a week both chemical and electrical synapses are formed by appropriate neurons. We are now examining the specificity with which such connections develop between identififed cells.